Because “The Dark Night of the Soul” is an allegory for the journey of the soul from the darkness, confusion, and suffering of the temporal and the secular world toward union with the powerful love of God, the poem is less a poem and more a philosophical exercise, an abstract treatise delivered in verse form in sculptured lines of varying length.

The form itself is rigid and clean, eight stanzas of five lines each, each section separated by Roman numerals to suggest the direction and momentum of a journey. Each section is delivered in a quintain, or a stanza with five lines. St. John of the Cross does not use any deliberate, predictive rhythm or anticipated rhyming scheme. In fact, he executes the poem in free verse termed pentastich quintain, a variation of quintain poetry associated since the Renaissance with religious or spiritual meditations, most notably the Italian cardinal Pietro Bembo (1470-1547) and the Spanish cleric-theologian Tirso de Molina (1579-1648). The form, decidedly simple and direct, was used to keep the focus on the theological argument and not allow the reader to be distracted by ornate or clever verse forms.